Backup Routing for BGP: Source Management Routing Scheme

Abstract

Despite of the high connectivity of the Internet, Border gateway protocol (BGP) often loses connectivity in the case of no alternate routes to destination. In this paper, we present source management routing scheme called SMR that provides a backup routing path for BGP on ASlevel. In SMR, virtual topology is defined by the virtual neighborhood relation over ASes which is decided by identifier of each AS. And then, routing on identifier of AS by itself can make each AS reachable. It is a novel way to integrate some physical topology into virtual topology to shorten the routes greatly. Considering a ring as a simplest virtual topology, this paper mainly discusses virtual ring SMR.
We evaluate the performance of virtual ring SMR by simulations on a real BGP topology. In the case of each AS only maintaining a route to one virtual neighbor, virtual ring SMR still provides a path to destination with low overhead. And then we mainly discuss what factors influence virtual ring SMR performance. More importantly, considering AS relationship and routing policy, although virtual neighbor paths can be compatible with the routing policy of ”valleyfree,” there are a number of routes on the virtual ring to violate this policy. How to deal with this problem is a key to implement SMR for BGP.